A kitchen sink always needs to a sink stopper to collect water in the sink or to enable water to drain. Generally, referring to FIG. 18, a conventional sink stopper has a sink drain (70) and stopper (80). The sink drain (70) has a pipe (71), and a bottom portion of the pipe (71) comprises a supporting portion (72). Moreover, a screw hole (73) penetrates through a central portion of the supporting portion (72). The stopper (80) comprises a lid (81), and an operating head (82) is formed at a top end of the lid (81) while a sealing piece (83) is coupled at a bottom end thereof. Furthermore, a telescopic shaft (84) protrudes from a central bottom portion of the sealing piece (83), and a lower end of the shaft (84) has a threaded section (85) which is configured to engage with the screw hole (73) of the sink drain (70), thereby connecting the stopper (80) with the sink drain (70). When the operating head (82) is pulled or pushed, the up or down motion of the shaft (84) can drive the lid (81) and the sealing piece (83) to stop or allow water to pass through and flow into the pipe (71).
However, the conventional sink stopper is disadvantageous because: (i) the threaded section (85) can only be engaged with the screw hole having a corresponding size, and the leaking is happened when the pipe (71) of the sink drain (70) is different-sized; and (ii) some of conventional sink stoppers even have no supporting portion (72) and screw hole (73), and the shaft (84) of the stopper (80) could not be successfully installed on the sink drain (70). Therefore, there remains a need for a new and improved design for a sink stopper to overcome the problems presented above.